title: An oxygen enrichment device for lowlanders ascending to high altitude.
abstract: BACKGROUND
  When ascending to the high altitude, people living in low altitude areas will suffer from acute mountain sickness. The aim of this study is to test the hypothesis that whether an oxygen concentration membrane can be made and used to construct a new portable oxygen enrichment device for individuals in acute exposure to the high altitude.
  
  
  METHODS
  The membrane was fabricated using vinylsiloxane rubber, polyphenylene oxide hydrogen silicone polymers, chloroplatinic acid and isopropyl alcohol. The membrane was assembled in a frame and the performance was tested in terms of concentration of oxygen, flow rate of oxygen enriched air, pressure ratio across the membrane and ambient temperature. Furthermore, the oxygen concentration device was constructed using the membrane, a DC fan, vacuum pump and gas buffer. A nonrandomized preliminary field test was conducted, in which eight healthy male subjects were flown to Tibet (Lhasa, 3,700 m). First, subjects wore the oxygen enrichment device and performed an incremental exercise on cycle ergometer. The test included heart rate (HR), saturation of peripheral oxygen (SpO2) and physical work capacity (PWC). Then, after a rest period of 4 hours, the experimental protocol was repeated without oxygen enrichment device.
  
  
  RESULTS
  The testing showed that the membrane could increase the oxygen concentration by up to 30%. Simulation test indicated that although the performance of the oxygen enrichment device decreased with altitudes, the oxygen concentration could still maintain 28% with flow rate of enriched air 110 cm3/s at 5000 m. The field test showed that higher SpO2, lower HR, and better PWC (measured by the PWC-170) were observed from all the subjects using oxygen enrichment device compared with non-using (P < 0.01).
  
  
  CONCLUSIONS
  We concluded that the new portable oxygen enrichment device would be effective in improving exercise performance when ascending to the high altitude.
authors.affiliation: School of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi 710032, People's Republic of China. tocooper@hotmail.com.
authors.forename: Guanghao
authors.initials: G
authors.lastname: Shen
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Wu
authors.forename: Chi
authors.initials: C
authors.lastname: Tang
authors.forename: Yili
authors.initials: Y
authors.lastname: Yan
authors.forename: Juan
authors.initials: J
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Guo
authors.forename: Da
authors.initials: D
authors.lastname: Jing
authors.forename: Tao
authors.initials: T
authors.lastname: Lei
authors.forename: Yue
authors.initials: Y
authors.lastname: Tian
authors.forename: Kangning
authors.initials: K
authors.lastname: Xie
authors.forename: Erping
authors.initials: E
authors.lastname: Luo
authors.forename: Jianbao
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000531:Altitude; D000532:Altitude Sickness / Q000628:therapy*; D006801:Humans; D008297:Male; D008397:Masks; D008567:Membranes, Artificial; D010102:Oxygen Inhalation Therapy / Q000295:instrumentation*; D055815:Young Adult
chemical_list: D008567:Membranes, Artificial